VF14K Vacuum Tube for use in the TELEFUNKEN or NEUMANN U47 or U48 microphones
Manufactured to be a direct "plug and play" retrofit for an original VF14M tube socket [with no modifications to circuit, cable or power supply required], the TELEFUNKEN VF-14k is employed in the TELEFUNKEN Elektroakustik U47 and U48 microphones. Anyone who owns an original U47 or U48 microphone knows that the supply of original German made VF14M tubes is exceptionally limited and frightfully expensive [if you can find a good one]. Since Neumann GmbH ran out of their supply of original tubes in the early 1960's, many attempts for substitute tubes have been offered with varying degrees of success.
After considerable research, TELEFUNKEN Elektroakustik located a glass tube, of obscure origin, originally manufactured for use in transoceanic telephone transmission. This tube captures all of the “ magic", "vibe" and "mojo" of the original tube. This is not a Nuvistor tube, nor an EF86, both of which have been previously used as substitutes for original VF14's. By carefully modifying by hand the actual physical shape of the tube, it is able to be placed inside an enclosure with identical pin orientation as an original VF14. The resulting sonic characteristics are extremely close to the original VF14, with nearly identical gain and distortion measurements.
The Telefunken VF14K has a 5-year warranty.